Medium
Security advisory
The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2019-16215
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 10:36 UTC · Revision 1
Source evidence
The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.
osv:CVE-2019-16215
Complete source record
{
"id": "c5016984538596f4ee2d9cdd2161065829f8cc24e51d03bbcce4538d000634a6",
"url": "https://osv.dev/vulnerability/CVE-2019-16215",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2019-16215",
"summary": "The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.",
"evidence": "osv:CVE-2019-16215",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2019-16215",
"aliases": [
"CVE-2019-16215"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/zulip/zulip",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "2bb3af1ade5bb3613dc88d44164abbe1230cd679"
},
{
"fixed": "5797f013b3be450c146a4141514bda525f2f1b51"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "2.0.5"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "5797f013b3be450c146a4141514bda525f2f1b51"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"2.0.4",
"2.0.3",
"2.0.2",
"2.0.1",
"2.0.0",
"2.0.0-rc1",
"1.9.0",
"1.9.0-rc3",
"1.9.0-rc2",
"1.8.0",
"1.8.0-rc1",
"1.7.0",
"1.6.0",
"1.5.0",
"1.4.0",
"1.3.13",
"1.3.11",
"1.3.10",
"1.3.9",
"1.3.8",
"1.3.7",
"1.3.6",
"1.3.5",
"1.3.4",
"1.3.3",
"1.3.2",
"1.3.1",
"1.3.0",
"enterprise-1.2.0",
"enterprise-1.1.5"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-16215.json"
}
}
],
"modified": "2026-10-20T10:50:46.214965539Z",
"provider": "osv",
"references": [
"https://blog.zulip.org/2019/09/11/zulip-server-2-0-5-security-release/",
"https://github.com/zulip/zulip/commit/5797f013b3be450c146a4141514bda525f2f1b51"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2019-16215",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 382131,
"published_at": "2019-09-18T12:15:10.91+00:00"
}